- Women aged between 20 and 40 with singleton pregnancies and BMI at recruitment > 30 kg/m^2 or a BMI> 25 kg/m^2 and the simultaneous presence of at least 1 of the following risk factors: age> 35 years, previous fetal macrosomia (> 4500gr), family history of diabetes (first-degree relative with type 2 diabetes mellitus), previous gestational diabetes mellitus.